Yutu is the tinamou, and it sits in the dark cloud series between the toad and the llama. The tinamou is a plump ground-dwelling bird of the Andes that flies badly and rarely, and whose response to danger is to freeze and rely on not being seen rather than to run or take off.
That behaviour is what the shape is read as showing. The dark form is squat and low, and the bird it names is a squat low bird that stays put. The Andean dark constellations tend to be read this way, by posture and by habit rather than by outline alone, which is a different practice from the Greek one of joining points into a figure.
In some recorded versions of the sequence there are two tinamou shapes rather than one, and the naming varies between communities, which is what one expects of a system transmitted orally over a large area with strong local variation.
The bird is also food and is hunted, and several of the dark animals are: the tinamou, the llama and, in a different sense, the fox that takes the llamas. The set is not a bestiary of the impressive. It is the working fauna of the high Andes, put in the sky in the order that the year needs them, which is a different principle from a sky of heroes and monsters.